Husbands first baby my 3rd

Im just about 28wks with my husbands first bio child. I’m really struggling with fears that he will show favoritism or preference for his bio baby and will feel differently about our/my 7 and 3 yr old. He claims them as his own but I know it’s inherently different because this baby will be his first biological child. I’ve asked if he felt like things would be different or he would treat them differently then the baby and he try’s to be reassuring but I’m still extremely overwhelmed with fear that they be left out. I suppose a lot of it could come from my own experiences as a child.

For those that have gone through bring in the first bio baby into a step parenting family could you share your experience with me? I’m literally losing sleep over it at this point. I know I should worry so much but I care a lot about how this could effect my 7 and 3yr old.